Overexpression of the epidermal growth factor receptor (EGFR) is caused by EGFR gene amplification and is sometimes associated with expression of a variant EGFR (deletion exon 2-7 or EGFRvIII). EGFRvIII mutation has oncogenic potential and is investigated as a potential therapeutic target. We genotyped the EGFRvIII mutation status in 252 surgically treated lung cancer cases. The presence or absence of EGFRvIII mutation was analyzed by real-time quantitative polymerase chain reaction (PCR) with mutation specific sensor and anchor probes. EGFR copy number was evaluated with PCR-based assay. EGFR mutation status at kinase domain has been examined and reported. EGFRvIII mutation was found on 8 of 252 patients. All patients were male, smokers, and 7 had squamous cell carcinoma. The mutation status was significantly correlated with pathological subtypes (squamous cell carcinoma vs. adenocarcinoma, p=0.0114). Sixty EGFR mutations at kinase domain exclusively existed with EGFRvIII mutations. EGFR gene copy number was significantly higher in EGFRvIII mutant (4.711+/-4.968) than in non-EGFRvIII mutant (2.284+/-1.224) (p=0.0001). EGFRvIII gene mutation might be one of the mechanisms of increased EGFR copy number. Further studies are needed to confirm the mechanisms of EGFRvIII mutations for possible anti-EGFR therapy for lung cancer.